unit 7 lesson 5
surface area of rectangular prisms practice
use the image to answer the question
9cm., 8cm., 5cm.
what is the surface area of the rectangular prism?
_ cm. ^2
To find the surface area of a rectangular prism, you need to calculate the area of each of the six faces and then add them together.
1. Calculate the area of the front and back faces:
Area = length x height
Area = 9cm x 5cm = 45cm^2 (front face)
Area = 9cm x 5cm = 45cm^2 (back face)
2. Calculate the area of the top and bottom faces:
Area = width x height
Area = 8cm x 5cm = 40cm^2 (top face)
Area = 8cm x 5cm = 40cm^2 (bottom face)
3. Calculate the area of the left and right faces:
Area = length x width
Area = 9cm x 8cm = 72cm^2 (left face)
Area = 9cm x 8cm = 72cm^2 (right face)
4. Add up all the areas:
45cm^2 (front face) + 45cm^2 (back face) + 40cm^2 (top face) + 40cm^2 (bottom face) + 72cm^2 (left face) + 72cm^2 (right face) = 314 cm^2
Therefore, the surface area of the rectangular prism is 314 cm^2.